One‐Pot Synthesis of Quinoline Derivatives Directly from Terminal Alkynes
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Sequential Ruthenium(II) and Acid Catalysis
作者:Min Zhang、Thierry Roisnel、Pierre H. Dixneuf
DOI:10.1002/adsc.201000278
日期:2010.10.9
A convenient one-potsynthesis of 2,3-disubstituted, 2,3,6-trisubstituted, and 2,3,6,7-tetrasubstituted quinoline analoguesfrom terminal alkynes via sequential ruthenium(II) and para-toluenesulfonic acid (p-TSA) co-catalyzed reactions is described. The catalytic process is shown to take place first via intermediate formation of an allyl ketone and then addition of an aniline derivative to the allyl
method of silyl dienol ethers via 1,4-Brook rearrangement–Wittig reaction sequence has been developed. This tandem reaction proceeded via the intramolecular silyl migration step, which enabled stereoselective formation of phosphorane intermediates. The reaction is operationally simple and high yielding, thus providing a new useful formula for silyl dienol ether synthesis.
aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant C═Cbondcleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible
An asymmetric synthesis of 5-halomethyl pyrazolines and isoxazolines which bear a tertiary stereocenter by catalytic halocyclization of β,γ-unsaturatedhydrazones and ketoximes is described. By using Brønsted acids of anionic chiral Co(III) complexes as catalysts, a variety of chiral 5-halomethyl pyrazolines and isoxazolines were obtained in good yields with high enantioselectivities (up to 99% yield